I agree with Dovster. I connect through FRA all the time and besides the lengthy taxing, etc, the lines at security can back up big time and they don't care who has to leave in a hurry or not.
Additionally, if you are traveling on two different airlines it's even worse. Sometimes an airplane will wait if an incoming flight of the same airline has a lot of passengers. But I can't imagine LH doing anything like that...
But for what it's worth, I wouldn't do it...
Happy Travels!
UG